Fluid pressure brake



March 17, 1936. E. E. HEWlTT FLUID PRESSURE BRAKE Filed June 20, 1931 3 Sheets-Sheet 1 ,om E

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March 17, E' E HEWlTT FLUID PRESSURE BRAKE Filed June 20, 1931 3 Sheets-Sheet 5 1N 1 EN T4012. ELLIS E. HEWI TT A TToREy.

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Patented Mar. 17, 1936 UNITED STATES PATENT OFFICE FLUID PRESSURE BRAKE Application June 20, 1931, Serial No. 545,647

38 Claims.

'Ihis invention relates to fluid pressure brakes and more particularly to the `type adapted to op-l erate in accordance with variations in brake pipe pressure.

For the purpose of economy, there is a continuing tendency to increase the number of freight cars hauled in a train and where heretofore a freight train might consist of cars, it is now desired to operate trains which include up to cars. l

The brake equipment at present employed was originally designed to operate in trains of up to 100 cars, but with the continuing increase in train length various operating diiculties are being encountered and especially in obtaining the intended operation of the equipment at the rear end of a long train.

One object of my invention is to provide an improved uid pressure brake equipment of the above type for obviatirig the diiculties encountered in long train operation. V

Other objects and advantages will appear in the following, more detailed description of the operation of the invention.

In the accompanying drawings; Fig. 1 is a diagency application position, the position of the.

triple valve devicebeing also that assumed when a service application of the brakes is effected; Fig. 4 is a diagrammatic View of a part ofthe emergency valve portion of the brake controlling valve device showing the parts in one position, which is assumed when an emergency application of the brakes is effected; and Fig. v5 is a viewsimilar to Fig. 4 but with the parts in another position which will be assumed at a later time when an emergency application of the brakes is effected. l

As shown in the drawings, the uid pressure brake equipment comprises a brake controlling valve device, an auxiliary reservoir I and emergency reservoir 2, preferably formed in a single casing having a partition wall 3 separating said reservoirs from each other, a brake cylinder 4, and a retainingV valvcdevice 5.

said facev and said emergency application valve device. 10

One feature of the invention is that the pipe bracket portion` 6, to which all pipe connections are made, contains a quick action chamber or reservoir I3, a quick service bulb or reservoir I4 to be either inserted into the cavity of the pipe 25' bracket for providing a quick service reservoir I4 of one volume or the cover plate may be turned over so that the volume within the concave por; tion of the cover plate is added to the volume of the cavity in the pipe bracket, thereby provid- -30 ing a quick service reservoir I4 of another or greater volume.

The strainer device I5 comprises an inner ringshaped, perforated retainer 20 and an outer ringshaped, perforated retainer 2| concentrically 35 mounted in the casing and held in place by a nut 22 having screw-threaded engagement in the casing. Hair or other suitable material is packed into the space between the retainers 20 and 2| and is adapted to remove impurities fromthe air 40 which is supplied to the annular chamber 23 surrounding the retainer 20I and which flows from f chamber 23 through the strainer to passage 24 within the inner retainer 20.

The combined centrifugal dirt collector and 45 cut-out cock I6 is preferably mounted directly on the pipe bracket and comprises the usual dirt separating chamber 25 having an inlet passage 26 in one side and an outlet passage 21 from near the center of said chamber and below the 50 inlet passage 26. The lower end of the dirt separating chamber 26 is open to a chamber 28 contained in a removable member 29, and foreign matter separated from the air stream which passes through chamber 25. is adapted to fall '55 into and collect in chamber 28. The member 29 is provided with an upwardly projecting pin 38 ed with the centrifugal dirt collector comprises a plug valve 32 rotatably mounted in the casing and adapted1 to be turned from the cut-in position shown in the drawings to a cut-out position by means of a handle 33` 'Ihe plug valve 32 is provided With a through opening 34 adapted in the cut-in position to connect passage 26 leading to thecentrifugal dirt collector to a passage' 35 leading through pipe 36 to the usual brake pipe 31.y

The brake pipe 31 is thus connected through the combined cut-out valve and centrifugal dirt collector I6 to a brake pipe passage 38 in the pipe bracket portion 6, which passage leads to the annular chamber 23 around the strainer device I5, and to the gasket face 8. When the cut-out plug valve 32 is turned by the handle 33 to cut-out position, communication between passages 35 and 26 is interrupted.

The service application valve device 9 comprises a piston 39 having at one side a chamber 48 which is open to the brake pipe passage 38 in thev pipe bracket portion through an aperture 4I in the nut 22, passage 24 in the strainer device I5, through said strainer device and the annular clamber 23. Said piston has at the opposite side a valve chamber 42 in constant communication with the auxiliary reservoir I through passage and pipe 43 and containing a main slide valve 44 and an auxiliary slide valve 45 adapted to be operated by said piston.

The service application piston 39 is provided with a stem 46 having a recess adapted to operatively receive the auxiliary slide valve 45. A portion of valve chamber 42, at the left hand end, is of enlarged diameter and is closed by a cover plate 41, which is provided with a projection 48 extending into said chamber. The projection 48 is provided with a bore for slidably receiving the end portion 49 of the piston stem 46. A collar or operating lug 58 is formed on the piston stem 46 adjacent the end portion 49, and the right hand side of this lug is adapted to engage the main slide valve 44 for moving said slide valve. 'I'he left hand side of said lug is adapted to engage a retarded release device comprising a member 5I movably mounted on the exterior surface of projection 48, and a spring 52 interposed between said member` and the cover plate 41. Inward movement of said member by said spring is adapted to be limited by a shoulder 53 formed in the valve chamber ,42. The main slide valve 44 is provided with a finger 54 preferably adapted to engage the member 5I at the sametime as the operating lug 58 on the piston stem engages said member.

` The end portion 49 of the piston stem' 46 is provided with a bore, the left hand end of which is closed by a screw plug 55. Said bore is'oiset from the center line of the piston stem and the lower portion of said bore at the right hand end is open to the valve chamber 42. Said bore contains a plunger 56 having a stem 51 slidably extending through a bore in the screw plug 55, and a spring 58 is interposed between said screw plug and plunger and normally maintains said plunger in engagement with the stem 46.

Preferably associated with said service application valve device is a quick service modifying valve device 13 comprising a casing secured to a suitable face of the service application valve device casing. A exible diaphragm 59 is suitably i mounted between said casings and has a chamber 68 at one side open to the atmosphere through a passage 6I, and a chamber 62 at the opposite side. Said diaphragm carries an operating pin 61 which is adapted to engage and movela poppet valve 63 away from a seat rib 64, said poppet valve being contained in a chamber 65 andisubject to the pressure of a spring 66. The operating pin 61 has an enlarged head portion 68 engaging one side of the diaphragm 59 and a central stud portion 89 extending through said diaphragm. A clamping ring 18 is mounted on the diaphragm over the stud portion 69 and a nut 1I is screw-threaded on to the stud portion 69 for clamping the diaphragm between the pin head 68 and the ring 10. A spring 12 is interposed between the ring and the wall of chamber 68 and is adapted to urge said diaphragm downwardly for unseating the poppet valve 63.

Preferably mounted on another face of the casing of the service application valve device is a reservoir release valve device 14 operative manually to vent fluid under pressure from the auxiliary reservoir I and .from the emergency reservoir 2.

'I'he reservoir release valve device comprises an auxiliary reservoir release valve 15 contained in a chamber 16 which is open to valve chamber 42 through a passage 11. Said valve is adapted to be normally held in engagement with a seat rib 18 by the pressure of a spring 19 and is provided with a iluted stem slidably extending through a suitable bore in the casing and into chamber 8l which is open to the atmosphere through a plurality of passages 82. An emergency reservoir release valve 83 is contained in a chamber 84 and is adapted to be normally held in engagement with a seat rib 85 by the pressure of a spring 86. Said valve has a uted stem 81 slidably extending through a suitable bore in the casing and into the atmospheric chamber 8I, said stem 81 being shorter in length than the stem 80 of the auxiliary reservoir release valve 15. One end of a sliding pin 88 is disposed in a bore in the casing of the service application valve device, while the other end extends through a bore in a clamping nut 89 having, screw-threaded engagement in the release valve casing. Disposed in the atmospheric chamber 8I and carried by the pin 88 is a member 98l which, when the pin 88 is moved downwardly in a manner to be hereinafter explained, is adapted to first engage the auxiliary reservoir release valve stem 88 so as toA move the valve 15 away from seat rib 18'. Upon further downward movement, the member 98 is adapted to engage the shorter stem 81 of the emergency reservoir release valve 83 and move said valve away from the seat rib 85, such downward movement of member 99 being opposed by the pressure of a. spring 9|.

Mounted between the reservoir release valve casing and a flange 92 on the clamping nut 89 is a. carrier device 93 having projections 94, each of which is provided near its end with a combined retaining and fulcrum pin 95. Disposed between the upper end of the operating pin 88 and the fulcrum pins 95 is a lever 96 provided at each end with a recess for engaging the respective pin 95. The pressure of spring 9| acting through the operating pin 88 normally holds the lever 96 in engagement with the pins 95. The lever 96 is provided with an operating lever 91,

'. able member |06 normally pressed into engagewhich, when moved either to the left or to the right, fulcrums on one or the other of the pins and exerts a downwardly acting force on the release valve operating pin 88, which is moved thereby and acts to unseat the auxiliary reservoir release valve 15 and, if the downward movement is suicient, to unseat the emergency reservoir release valve 83.

The emergency application Valve portion 'comprises an emergency piston 98 having at one side a chamber 99 open to the brake pipe 31 through.

passage |00, the strainer device I5 and the brake pipe passage 38, and at the opposite side a valve chamber |0| open through passage |02 to the quick action chamber I3 in the pipe bracket portion 6, said valve chamber containing a main slide valve |03 and an auxiliary slide valve |04 adapted to be operated by said piston.

A portion oi the valve chamber |0| at the right hand end is of enlarged diameter and this end of said chamber is closed by a cover plate |05. Disposed in -the enlarged portion of said valve chamber is a resistance device comprising a movment with a shoulder |01 in said chamber by means of a spring |08. The member |06 is provided with a guide portion slidably mounted on the external surface of a projection |09 from the cover plate |05. l

The emergency piston 98 is provided with an operating stem ||0 having a cavity for operatively carrying the auxiliary slide valve |06, and having a guide portion at its end slidably disposed in a bore in the projection |09. Adjacent the guide portion the stem ||0 is provided with a collar ||2,` which is adapted to engage the movable member |06 and at the time oi such engagement, a linger H3 projecting from the main slide valve |03 is also adapted to engage the member' |06.

The guide portion is provided with a bore closed at one end by a screw plug H0 and partly open at the other end to the valve chamber |0|. Disposed in said bore is a movable plunger ||5 having a stem ||6 slidably mounted in a suitable bore through the screw plug IM. A spring ||1 is disposed between said screw plug and the plunger I|5 for opposing inward movement of said plunger. 4

The main slide valve |03 is adapted to be pressed into engagement with its 'seat by a force acting throughA a rocking pin ||8 vwhich freely passes through an opening in the emergency piston stem ||0 'and recess H9.

The upper end of the rocking pin ||8 is of enlarged area and engages a flexible diaphragm |20 mounted in the casing. y The diaphragm |20 is thus subject on one side to the pressure of fluid in the emergency valve chamber |0| and has at the other side a chamber |2| containing va. pressure exerting member |22 engagingl the diaphragm |20 and acted upon by a spring |23.

The face of member |22 engaging the diaphragm |20 is recessed to receive a smalllbutton-shaped boss |24 on the diaphragm, and the upper end of the rocking pin ||8 is also. recessed to receive-l a button-shaped boss |25 on the other side of said diaphragm, the engagement of said bosses in their respective recesses. being adapted to maintain the member |22 and rocking pin ||8 in operative alignment with each other and with the diaphragm.

Associated with the emergency valve device is vthe usual quick action mechanism |53 comengages said slide valve in a l prising a quick action piston |26 having at one side a chamber |21., ithe open end of which is closed by a cover plate |28`and at the other side achamber |29 open to the atmosphere through a passage |30. The quick action piston is operatively connected by a stem |3| to a brake pipe vent valve preferably in the form of a valve piston |32 which is contained in a chamber |33, said chamber being open to the brake pipe through passage |34 leading to the brake pipe passage 38 in the pipe bracket portion. The vent Valve |32 is normally pressed into engagement with a seat rib |35 by means of a spring |36. The quick action piston chamber |29 has an apertured partition wall |31 and on one side of said wall is disposed a valve seal |38, said seal being held in place by a flanged ring |39 having screw-threaded engagement with the side of the aperture through said partition wall. This seal |38 is adapted to be engaged by a seat rib |00 on the quick action piston |26 so as to prevent leakage of iiud under pressure from piston chamber |21 past said piston, under certain conditions of operation.

Contained within the casing of the emergency lapplication valve device is an inshot Valve mechanism |52 which is operative, when effecting an emergency application of the brakes, to control the rateat which flnid under pressure is initially supplied to the brake cylinder, said mechanism comprising a poppet valve M l contained in a chamber |02 and adapted to be pressed into engagement with a seat rib |03 by a spring |40, and a valve piston |35 having a finger |06, for moving said poppet valve ."away from the seat rib |03. Normally, said valve piston is urged into engagement with a seat rib |01 by a spring |08 contained in a chamber |09 at one side of said valve piston, and in said position the poppet valve |0| is maintained away from the seat rib |03. The valve piston chamber is open at all times through passage |50 to a small chamber or reservoir |5|.

Mounted on a face of the emergency valve casing is a timing valve device |50 and a cut-out Valve device |55, both of said devices being preferably contained in one casing |56. The timing Valve device |50 is adapted to control the supply| of uid under pressure to the brake cylinder, in eiecting an emergency application of the brakes, after the operation of the inshot valve mechanism |52, and comprises a flexible diaphragm |51 having at'one side a chamber |58 connected by a passage |59 to the emergency slide valve chamber |0| and containing a. 'diaphragm follower head |60 engagingv said diaphragm. The follower head |60 is provided with a stem |6| slidably disposed in a suitable bore in a lug |62 projecting from the casing. At the other side of said diaphragm is a projection"|63 having at its outer end a 'seat rib |64 surrounding a passage |65 extending centrally thrugh said projection, and said diaphragm is adapted to engage said seat rib. Surrounding the projection |63 and engaging said diaphragm is a spring seat |66 acted upon by a spring |61. The cut-out valve device |55 is provided 'for rendering the inshot valve mechanism |52 ineffective under certain conditions as will be fully described later, and comprises a flexible diaphragm |68 having at one side a chamber |69 open to the atmosphere through a passage |10 and containing a diaphragm follower |1| urged into engagement with said diaphragm by a spring |12, which is adapted to normallymaintain said diaphragm in engagement with a seat rib |13.

The diaphragm follower |1| is provided with a guide pin |14 slidably carried in a bore of a lug For the purpose of by-passing the strainer device I5 in the pipe bracket portion 6 in case said strainer device becomes clogged, two check valves, |16 and |11, are provided in the emergency valve portion. The check valve |16 is contained in a chamber |18 and is pressed into engagement with a seat rib |19 by a light spring |80 and the check valve |11l is contained in a chamber 8| and is pressed into engagement with a seat rib |82 by a light spring |83. Said check valves normally cooperate in closing communication from the brake pipe passage 38 through passage |34 to passage leading to the passage 24 Within the v strainer device, but the check valve |16 is adapted to be opened to permit iiuid under pressure to iiow from passage |34 to passage |00,.and the check valve |11 is adapted to permit flow of fluid under pressure in the reverse direction.

The retaining valve device is of the usual construction having a cut-out position in which it is inoperative, and a cut-in position in which it is adapted to permit the release of fluid under pressure from the brake cylinder 4 to the atmosphere until the brake cylinder pressure is reduced to a predetermined degree, at which time it prevents any further reduction in brake cylinder pressure from occurring.

In operation, to vinitially charge the brake equipment, fluid under pressure is supplied to the brake pipe 31 in the usual manner and flows from said brake pipe through pipe 36, the combined cut-out valve and centrifugal dirt collector I6 to the brake pipe passage 38 in the pipe bracket portion 6 and from passage 38 through the annular chamber 23, and through the strainer device |5 to passage 24 and from thence through passage 4| to the service application valve or triple valve piston chamber 40 and also from passage 24 through passage |00 to the emergency valve piston chamber 99.

With the triple valve piston 39 in the full release position shown in Fig. 1 of the drawings, fluid under pressure flows from piston chamber 40 through a feed passage |64 to valve chamber 42 and from thence through passage and pipe 43 sition shown in Fig. 1 of the drawings, fluid under pressure flows from the emergency piston chamber 99 through a choke |88 to passage |02 leading to the quick action chamber I3 and to the emergency valve chamber |0 Fluid under pressure flows from the emergency valve chamber through passage |59 to diaphragm chamber |58 of the timing valve device |54, and if for any reason .the pressure builds up more rapidly in the emergency valve chamber |0| than in the emergency reservoir 2, fluid under pressure flows from said chamber past two check Valves |89 and |90, arranged in series, to the check. valve chamber 9|, and from thence through passage |92 to passage |86through which fluid under pressure is supplied to the emergency reservoir 2. 'I'he check valve |90 is subject to the pressure' of a light spring |93 which is provided for seating said check valve upon substantial equalization of pressures acting on the opposite sides thereof. Fluid at the pressure in check valve chamber |9| flows through a choke |94 and passage |95 to the dlaphragm chamber |2I.v 'I'he fluid pressures thus equalize on the opposite sides of the loading daphragm |20, and only the pressure of spring |23 acts through the rocking pin ||8 on the main emergency slide valve |03.

In the release position of the triple valve device 9 the brake cylinder 4 is open to the atmosphere through pipe and passage |96, past the inshot check valve |4|, through passage |65, cavity |91 in the main triple valve slide valve 44, passage and pipe |98 and the retaining valve device 5 which is normally carried in the cut-out position and will be so considered unless otherwise specified. V

The small chamber or reservoir |5| in the emergency valve portion, and the connected inshot valve piston -chamber |49 are open to the atmosphere through passage 262, cavity |99 in the main emergency slide valve |03 and passage |65 through which the brake cylinder 4 is connected tothe atmosphere. -With the brake cylinder passage |96, which isl open to the right hand face of the inshot valve piston |45, at atmospheric pressure, spring |48 urges said valve piston into engagement with the seatrib |41, and'in this position, the seated area of said valve piston outside of the seat rib |41 is open to the atmosphere through a passage 200 leading to the valve piston chamber |49.

The seatedarea of the timing valve diaphragm |51 within the seat rib |64 is open to the atmosphere through passage |65 and the seated area of Fluid at brake pipe pressure flows from the brake pipe passage 38 in the .pipe bracket portion 6 to passage |34 leading to the vent valve chamber |33 and to the by-passv check valve chambers 20| and |8|. The vent valve |32 is normally pressed into engagement with the seat rib |35 on account of the quick action port 203 in the main emergency slide valve being lapped by the auxiliary slide valve |04, vsaid port nrmally registering with passage 202 leading to'the quick laction piston chamber |21 which is thus at atmospheric pressure due to the connection to the atmospheric chamber |29 through choke 204 in the piston |26 and a. leakage groove 205 by-passing said piston. f

Fluid at brake pipe pressure is also supplied from passage |00 in the pipe bracket portion 6 to the by-pass check valve chamber |18 and acts on the adjacent faces of the check valves |11 and |16. Said check valves are thus balanced by fluid pressure and the pressure of spring |80 on check valvey |16 and spring |83 o |11 holds said check valves seated.

When the triple valve device is in release position, the quick service modifying valve diaphragm chamber 62 is open to the atmosphere through passage 206, cavity 201 inthe main slide valve 44, port 208, choke 209, port 2| 0, retarded release choke 2| I, cavity 91 and passage and pipe |98 leading to the retaining valve device 5. With the diaphragm chamber 62 thus open to the atmosphere, spring 12 holds the diaphragm 69 de,-

n check valve.

ected downwardly, in which position, the check valve 63 is unseated, which opens the quick servlce reservoir I4 to the atmosphere through passage 2|2, check valve chamber 65 and diaphragm chamber 62.

In full release position of the triple valve main slide valve 44, fluid under pressure is supplied from the valve chamber 42 through the service port 2 I3 to the seating face of the auxiliary slide valve 45, and a cavity 2I4 in said slide valve is kopen through port 2 I5 in the main slide valve 44 to passage which is charged with uid at brake pipe pressure. Thus, a certain predeterned area of the seating face of the auxiliary slide valve 45 is subject to fluid under'pressure which is adapted to reduce the force required to' move said slideA valve to quick service position, as will be hereinafter described, so as to cause said triple valve piston 39 and auxiliary slide valve 45 to move upon a reduction in brake pipe pressure of a predetermined light degree. The main slide valve 44, however, is loaded in full release position, so as"t`o require a greater, but predetermined, degree of reduction in brake pipe presf sure to move it, said main slide valve being loaded by connecting a cavity 260 inthe seating face of said slide valve to the atmosphere through a port 2I6, choke 2|1 and a port- 2|8 which registers with the atmospheric passage |98 leading to the retaining valve device 5.

A service application of the brakes is effected upon a gradual reduction in pressure in the brake pipe 31 in the usual manner. As hereinbefore described, the brake pipe 31 communicates with the triple valve piston chamber 40 and emergency valve piston chamber 99, and as a result, the pressure in said chambers gradually reduces with brake pipe pressure.

Upon a predetermined light reduction in pressure in the triple valve piston chamber 40, the pressure of fluid in the triple valve chamber 42 shifts the triple valve piston 39 and auxiliary slide valve 45 toward the right hand and relative to the main slide valve 44. In thus moving, the` piston 3'9 rstcloses the feed passage |84 so as to prevent back ow of uid under pressure from the valve chamber 42 to the piston chamber 40, after which the plunger 56 engages the end of the main slide valve 44. Further movement of said piston and auxiliary slide valve to the right relative to the main slide valve is thus resisted by the spring 58. Said spring, however, is of such value that only a slight increase of brake pipe reduction in piston chamber 40 is required to compress it and permit the piston and auxiliary slide valve to move to quick service position. It will be noted that the piston 39, on account of its sensitivity to pressure differentials, quickly responds to a brake pipe reduction to close the feed passage |84 and although movement to the quick service position is opposed by thespring 58, said piston still moves to quick service position upon a slight increase of reduction in brake pipe pressure, the total reduction required tomove said piston to quick service' position being,

for instance, less than one pound.

In quick service position of the auxiliary slide valve 45, the cavity 2 I4 connects port 2|5 in the main slide valve 44 to port 208 in said slide valve.

Port 2I5 registers with passage |00 which is at all times open to the brake pipe 31 through the strainer device I5 and the brake pipe passage 38 in the filler portion 6, so that iiuid under pressure is permitted to flow from the brake pipe to cavity 2I4 in the auxiliary slide valve and from diaphragm chamber 62, from which fluid under Ipressure flows past the check valve 63 to chamber 65 and from thence to the quick service reservoir I4. 'I'his produces a sudden, local quick service reduction in pressure in the brake pipe 31 for hastening the operation of the brake controlling device on the next car in a train which then operates in a similar manner, and in this way a quick serial response to the brake pipe reduction is transmitted from one car to the next throughout the length of the train.

It will be noted that port 208 through which fluid under pressure is supplied to -the quick service reservoir I4, is also open to the atmosphere,

-in release position of the main slide valve, throughI choke 209, port 2|0, retarded release choke 2II, cavity |91 and the retainer valve passage |98. No appreciable reduction occurs through the two chokes 209 and 2| I to the atmosphere however, and the eiiect of the quick service reduction in brake pipe pressure and in the pressure in the triple valve piston chamber 40 causes the triple valve piston to promptly move to Service position, in which it engages the gasket I0. The lug 50 on the end of the piston stem 46 just engages the main slide valve 44 in quick service position, so that movement of the piston to service position also shifts the main slide valve from the release position to thelservice position, as shown in Fig. 3, in which position the quick service reservoir is disconnected from the atmosphere and passage 206 from said reservoir is connected to passage |00 from the brake pipe through the port 2|6 in the main slide valve, choke 2|1 and port 2|8, so that in service position further quick service venting of uid under pressure from the brake pipe to the quick service reservoir occurs. In quick service position of the triple valve device, the reduction in brake pipe pressure caused by venting fluid under pressure from the brake pipe to the quick service reservoir I4 is adapted to move the triple valve parts to service position, in which position a further reduction in brake pipe pressure is eiected by flow to the quick service reservoir until Ithe brake pipe pressure is equalized with the pressure in said reservoir. brake pipe pressure is thus limited and is adapted to hold the triple valve parts in a position for supplying iiuid under pressure to the brake cylinder to develop an eiective brake cylinder pressure. This nal quick-service iiow is however limited to a slow rate by the choke 2 I 1 so as to dampen or smooth out surges or uctuations in pressure in the brake pipe which may have been'created by the initial sudden and local quick service venting.

In service position of the triple valve slide valves 44 and 45, the service port 2I3 is uncovered by the auxiliary slide valve 45 and registers with passage |65. 'Ihis permits fluid under pressure to flow from the triple valve chamber 42 and the connected auxiliary reservoir I, which is open to said chamber byway of pipe and passage 43, to passage |65 and from thence past the normally unseated inshot valve |4I in ther emergency valve portion to passage |96 leading to the brake cylinder 4.

Fluid at the pressure supplied throughA passage |65 to the brake cylinder 4 also ows from said passage through cavity |99 in the main emergency slide valve |03 to passage 262 leading to the small 'chamber or reservoir I5| and then flows from said reservoir through passage |50 to the valve 'I'his nal quick service reduction inr piston chamber I 49 and from thence through passage 200 to the outer seated area on the other side of said valve piston. The inner seated area on said other side of said valve lpiston is subject to the pressure of iluid from passage |65 supplied to passage |95. Thus, the opposing uid pressures acting onthe inshot valve, piston |45 are equal, and spring |48 maintains said valve piston and the poppet valve I4I inhthe position shown in Fig.- 1.

In the manner just described, fluid under pressure is supplied by the service application Valve or triple valve device 9 to the brake cylinder 4 upon a gradual reduction in brake pipe pressure to effect a service application `of the brakes and it will be noted that theinshot valve piston |45 and poppet valve I4I do not' move from their normal position.

In effecting a quick service reduction in brake pipe pressure, when the pressure'in the modifying valve diaphragm chamber v|52 builds 'up to a low degree, such as for instance 6 pounds, the diaphragm 59 is deflected upwardly against the op` posing pressure of spring 'I2 contained in the atmospheric chamber 60. `This movement of said diaphragm pulls the operating pin 61 away from the poppet valve 03 and .permits spring 66 to control said valve. Spring 66 is of small value however, being merely suiiicient to seat said valve, so thatwhile fluid under pressure continues to be supplied from the brake pipe to the diaphragm chamber 62, a smallpressure differential on said valve permits fluid under pressure to flow from the diaphragm chamber 62 to the quick service reservoir I4 to effect the operation hereinbefore described. The check valve 63 and diaphragm have no effect in eectingan application of the brakes y in the manner hereinbefore described but are only adapted to annui the quick service action after the initial-application of the brakes in cycling as Will be fully described hereinafter.

Upon ai service reduction inpressure in the emergency piston chamber 99, the emergency piston 98 and auxiliary slide valve |04 are shifted toward the left, relative tothe main slide valve |03, by the quick action chamber pressure in valve chamber IOI. This movement of the auxiliary slide valve |04 brings 'a port 22| in said slide valve into registration with a port `222 Athrough the main slide valve. Port 222 registers with an atmospheric passage 223 through which fluid under pressure is adapted to be vented from the emergency valve chamber IOI and the connected quick action chamber I3. The rate at which the pressure of fluid isihus reduced in valve chamber |0| is substantially equal to the service` rate of reduction in pressure in the emergency piston chamber 99 and is thus adapted to substantially4 destroy the operating pressure dierential on the piston 99. In the service position, the plunger |I5 in the emergency valve piston stem I I0 is adapted to just engage the-right hand end of the main slide valve |03, so that further movement of the piston and auxiliary slide valve tothe left and beyond the service position is resisted by` the pressure of spring II'I.

In order to limit the degree of brake application, the brake pipe pressure is only reduced an amount sufficient to eiiect the desired service application of the brakes. Then, when the auxiliary reservoir pressure acting in the triple valve chamber 42 is reduced by ow through the service port 2I3 and passage |65 to the brake cylinder 4 an amount substantially equal to the degree of brake pipe reduction in the triple valve` piston chamber 40, the triple valve piston 39 and auxiliary slide valve 45 are moved from service position to the left to service lap position in which said piston engages the end of the main slide valve 44 and stops. This movement is initiated by the pressure of spring 58 in the triple valve piston stem 46 which acts against the main slide valve and is adapted to pull the piston away from the gasket I 0 or in other Words to break the seal between said piston and gasket. After the piston seal is thus broken, a slight pressure differential on said piston, caused by the pressure in valve chamber 42 reducing slightly below the brake pipe pressure in piston chamber 40, moves said piston and auxiliary slide valve to lap position, in which said slide valve laps the service port 2 I3.and prevents further flow of fluid under pressure from the auxiliary reservoir to the brake cylinder 4.

When the degree of brake pipe reduction is thus limited, the quick action chamber pressure in the emergency valve chamber IOI continues to reduce through port 22| in the auxiliary slide valve |04 until the pressure in said chamber is slightly below the brake pipe pressure in piston chamber 99, at which time the pressure diil'erential created on the emergency piston 98 shifts said piston and the auxiliary slide valve |04 back to the release position as shown in Figgl, in which position port 22| is moved out of registration with port 222 through the main slide valve |03 and further reduction in pressure in the emergency vvalve chamber IOI is thus prevented.

In service position of the triple valve, the cavity 260 is open to the passage |00, which is at all times charged with fluid at brake pipe preseasier to obtain a release of the brakes and also` ensures movement of the triple valve piston 39 and slide valves 44 and 45 from service position to release position upon a slow increase in brake pipe pressure as will now be described.

To effect a release of, the brakes after an application, fluid under pressure is supplied to the brake v-pipe 31 and ows from said brake pipe to the triple valve piston chamber 40 and emergency valve piston chamber 99 in the manner hereinbefore described.

In supplying fluid under pressure to the brake pipe to eiect a release of the brakes, it is customary to initially turn the usual brake valve device to release position in which :fluid under pressure is supplied directly from the main reservoir throu'gh the brake valve device to the brake pipe and then after a predetermined interval of time,"

which is varied, as in accordance with the'length of the train, the brake valve device is turned to the usual running position, in whichV the pressure of fluid supplied to the brake pipe is reduced by a feed valve device to that normally carried in thebrake pipe.

The initial supply of uid at high pressure to the brakeV pipe rapidly increases the brake pipe pressure in the front portion of the train and at or near the locomotive the brake pipe pressure 4may be increased to substantially that carried in the main reservoir. This high head of pres- The rapid increase in brake pipe pressure at the front end of the train builds up a differential on the triple valve piston 39 which causes said piston to move to release position, in which position collar 50 on the piston stem 46 and linger 54 on the main slide valve 44 engage the retarded release member 5|. In this full release position the feed passage |84 is open so that iluid under pressure is permitted to ow from the piston chamber 40 to the valve chamber 42, but the flow capacity of said feed passage is insuicient to offset the rapid rate of increase in brake pipe pressure in piston chamber 40. As a result, a sufllcient pressure differential is built up on said piston to move said piston and the slide valves 44 and 45 to retarded release position, as shown in Fig. 2, against the resisting pressure of the retarded release spring 52. In this position, the piston 39 engages a stop rib 224 in the casing.

In the retarded release position, the rate at which uid under pressure is permitted to flow from the piston chamber 40 to the valve chamber 42 is restricted by a feed groove 225 which is'of smaller flow area than feed passage |84. addition to the restricted iiow through feed 1 groove 225, fluid under pressure is also supplied from the fully charged emergency reservoir through pipe |81, passage |86, cavity and port |85 and choke 226 in the main slide valve 44 to valve chamber 42 and from thence through passage and pipe 43 to the auxiliary reservoir l. Due to thus restricting the supply of fluid under pressure from the brake pipe to the auxiliary reservoir and on account of supplying fluid under pressure from the emergency reservoir to the auxiliary reservoir, the amount of fluid taken from the brake pipe at the front end of the train is small and this hastens the rate at which the brake pipe is charged at the rear end of the train. The choke 228 limits the rate at which fluid under pressure ows from the emergency reservoir 2 to the auxiliary reservoir to such an extent that, after the brake valve device is moved from release position to running position and the brake pipe pressure at the front end of the train drops to or below that supplied by the feed valve device, the auxiliary reservoir pressure in valve chamber 42 will be less than the brake pipe pressure in piston chamber 40, so as to prevent undesired movement of the triple valve device to quick service or service position.

In retarded release position, the brake cylinder 4 is open to the atmosphere through pipe and passage |96, past the inshot poppet valve |4|, through passage |65, cavity |91 in `the main triple valve slide valve 44, through the retarded release choke 2| I, port 2|0 and passage and pipe |98 leading tothe retaining valve device 5. Fluid under pressure is thus vented fromthe brake cylinder at a rate controlled by the retarded release choke 2| which permits a. slow release of the brakes at ,the head end of the train.

- Fluid under pressure is also vented from the quick service, modifying valve diaphragm chamber 62 through passage 206, cavity 201 in the main slide valve 44, port 208, choke 209 and through the vented port 2 0. When the pressure in the diaphragm chamber 62 is thus reduced to a degree less than the pressure of wspring 12, said spring deflects said diaphragm downwardly, thereby unseating the poppet valve 83. This opens-communication fro-m the quick service reservoirl I4 through passage 2|2 to the diaphragm chamber 62, so that uid under pressure is vented from the quick service reservoir as the brakes are released.

In the retarded release position of the main triple valve slide valve shown in Fig. 2, it will'be noted that a portion of the seatingface of the main slide valve 44, at the left hand end extends out and into the valve chamber 42, thereby being subjected to the pressure'of fluid in said valve chamber. In addition, one end of passage 26| is uncovered by the right hand end of the main slide valve and permits fluid under pressure to ilow from the valve chamber 42 to the cavity 260. By this means a predetermined area of the seating face of the main slide valve at each end is unloaded in retarded release position, so that after the brake valve device is moved from release to running position and the pressures acting on the opposite sides of the triple valve piston 39 become substantially equal, the pressure of the retarded release spring 52 is permitted to readily shift the triple valve piston 39 and slide valves 44 and 45 to the full release position shown in Fig. `1, in which the feed passage |84 is opened and port 2|5 registers with passage |00 so that upon a succeeding application of the brakes, the quick service action will be effective. It will be evident that if the 'main slide valve were not thus moved from retarded release position to full release position, quick service action would not be effective upon a succeeding application of the brakes.

In full release position of the triple valve slide valves, fluid under pressure may continue to flow from the emergency reservoir 2 rto the valve chamber 42 and auxiliaryreservoir by Way of port |85 and choke 228 in the main slide valve 14, but after equalization of the pressures in both of said reservoirs, iluid under pressure supplied through feed passage |84 to valve chamber 42 completes the charging of the auxiliary reservoir up to the -pressure carried in the brake pipe, and as the auxiliary reservoir pressure is built up, uid under pressure flows from the valve chamber 42 through port |85, passage |86 and pipe |81 to the emergency reservoir 2, thereby recharging said reservoirs.

In the full release position of the triplev valve slide valve 44, passage |65 from the brake cylinder is open directly through cavity |91 to the release passage |98 leading to the retaining valve device 5, so that the final release of fluid under pressure from the brake cylinder is at the standard rate.

In effecting a service application of the brakes, the emergency piston 98 and auxiliary slide valve |04 move toward the left to vent fluid under pressure from the emergency valve chamber and quick action chamber, but after the pressure in said chambers reduces substantially equal to or slightly below the reduced brake pipe pressure, said piston and valve are returned to their normal or release position in which the choke |88 is open to the piston chamber 99, as hereinbefore described. In releasing the brakes after a lservice application, the flow area of the choke |88 is so small that the initial high brake pipe pres sure at the head end of the train, creates suflcient differential 'on piston 98 to move said piston and the slide valves |03 and |04 to their extreme right hand positiyn, in which said piston engages a stop lug 221 in the casing and in moving to said position, the member |06 is moved against the pressure of spring |08 and compresses said spring. This operation of the emervses brakes after a service application of the brakes and in fact is merely incidental.

The volume of the quick action chamber |3 and the connected emergency slide valve chamber |0| is not great, and even though the port |88 in the quick action piston chamber wall is small, there would be a possibility on cars at the head end of a train of charging said chambers to a pressure greater than normally carried in the brake pipe, in which case the emergency valve device would tend to operate to effect an undesired emergency application of the brakes, as will be hereinafter fully described, when the brake pipe pressure reduces to normal upon movement of the brake valve device to running position. In order to prevent said chambers from thus becoming overcharged in releasing the brakes, the emergency valve chamber 0| is connected to the emergency reservoir 2 through a passage 228, past the check valves |89 and |90, through passages |92 and |86 and through pipe |81. 'I'his prevents the pressure in said chambers from ever exceeding emergency reservoir pressure which at no time becomes higher than brake pipe pressure. i

In releasing the brakes after .a service application, the relatively slow rate of increase in brake pipe pressure at the rear end of the train moves the triple valve device only to full release position into engagement with the retarded release lmember 5| land in Whichthe feed passage |84 is opened. The flow capacity of feed port |84 is sufficiently great to offset the slow rate of increase in brake pipe pressure and limit the difierential on the triple valve piston to a degree insufficient to cause said piston to compress the retarded release spring 52.

In the :full release position of the triple valve device, fluid under pressure is supplied from the emergency reservoir`2 to the auxiliary reservoir at the same time as from the brake pipe through thevfeednpassage |84, thereby accelerating the charging of the auxiliary reservoir up to equalization with the emergency reservoir, after which both reservoirs are charged up to brake pipe pressure by fluid under pressure supplied through the feed passage |84. Fluid under pressure is vented from the brake cylinder 4 in the same manner as hereinbefore described except that the complete venting occurs directly from passage through cavity |91 in the main slide valve 44v and passage and pipe |98y leading to the retaining valve device 5, so that there is no retarding of the release of brakes as occurs in retarded release position of said slide valve. pressureis also vented from the quick service reservoir through the modifying valve device 13, passage 206, port 208, choke 209, port 2|0, retarded release choke 2||, cavity |91, and passage and pipe |98, the effect of said chokes on such venting being merely incidental, said ,chokes v being provided for other purposes as hereinbefore described. Y 4

The slow rate of increase in brake pipe pressure at the rear end of the train has no operative effect upon the emergency application valve piston 98 which returned to release 'position after the quick action chamber pressure in valve chamber |0| reduced to slightly below brake pipe pressure in effecting a service application of the brakes, for the reason that said quick action chamber and valve chamber charge through the choke |88 at substantially the same rate as the brake pipe pressure increases in the pisto chamber 99.

Fluid under To effect an emergency application of the brakes, fluid underpressure is suddenly vented from the brake-pipe 31 and the connected triple valve piston chamber 40 and emergency valve piston chamber 99 and the triple valve device operates in the same manner as in effecting a service application ofthe brakes, to supply fluid under pressure from the auxiliary reservoir through the slide valve chamber 42 and service port 2| 3 to passage |65 through which uid under pressure is supplied to the brake cylinder 4.

At substantially the same time as the triple valve .device operates upon an emergency reduction in brake pipe pressure, the quick action chamber pressure acting on the righthand side of the emergency piston 98 shifts said piston and the slide valves |03 and |04 outwardly to emergency position, in which said piston engages the gasket |2. In thus moving to emergency position, therey is a slight hesitation of the piston at the time thecollar ||2 .on the piston stem ||0 engages the right hand end 'of the main slide valve |03, during which, the differential onthe vemergency piston increases sufficiently to'move the main slide valve to emergency position. At

' the timethis hesitation occurs,` however, the

port 203 through the main slide valve |03 is unpermits fluid under pressure tofiow to passage 202 and from thence to the quick action piston `chamber |21. When the emergency piston and slide valves move Vto* emergency position however, the passage 202 is uncovered by the right hand end of said slide' valve, which permits further flow of iluid under pressure from the emergency valve chamber |0| and the connected quick action chamber |3 to the quick action piston chamber |21.

The pressure of fluid thus supplied to the quick action pistonv chamber |21 shifts the piston |26 to the left into engagement with the seal |38. This movement shifts the vent valve |32 away from the seat rib |35, thereby opening the brake fluid has to be supplied to the quick action piston chamber to effect opening of the vent valve |32, and by this means the brake pipe is locally vented in the shortest possible time. It will be noted that if for rany reason it is impossible for the emergency piston 98 to move the main slide valve |03 from the release position to emergency position, the operation of the quick action piston |26 will however be obtained by fluid under pressure supplied through the ,port 203 in said main slide valve.

Fluid under pressure is gradually vented from the emergency slide valve chamber |0| and quick action chamber 3 through the choke 204 in the quick action piston |26 to the atmospheric cham- .ber 29, and when reduced to a predetermined degree, the pressurev of spring |38 on the vent valve |32 returns said valve into engagement with thc seat rib |35, and thus piston |26 to the position shown in the drawings. ',Ihe rate at which the quick action chamber pressure reduces through the choke 204l is however sufficiently slow as to ensure the complete venting of uid under pressure from the brake pipe.

The choke 204 through the quick action piston |26 is small and said piston is pressed into engagement with the seal |38 by fluid under pres- Ysure supplied to chamber |21, so that possible leakage of fluid under pressure past the periphery of the piston is prevented, thereby ensuring that the vent valve 32 will be held open for a definite predetermined period of time governed entirely by the size of said choke and the volume of the quick action chamber and emergency valve chamber. In fact, choke 204 is so small that possible leakage from the emergency valve chamber past the main slide valve |03 or auxiliary slide valve |04 to passage 202 might at some time exceed the capacity of said choke, and cause said piston to unseat the vent valve |32 when not desired. In order to prevent such from occurring, the leakage groove 205 is provided to connect the opposite sides of said piston when it is in its normal position, said leakage groove having a relatively large flow are'a.

In emergency position of the emergency slide valve |03, a cavity 230 in said slide valve connects passage |86 from the emergency. reservoir 2 to passage |65 to which fluid under pressure is being supplied by the triple valve device from the auxiliary reservoir Fluid under pressure thus supplied from the auxiliary reservoir and emergency reservoir 2 to passage |65 flows to the inshot poppet valve chamber |42 and from thence past the inshot valve piston operating finger |46 tothe inner seated area of said valve piston and to passage |96 leading to the brake cylinder 4 and rapidly builds up a pressure in said brake cylinder.

Passage 262 from the small reservoir is lapped in emergency position of the emergency slide valve, and since passage 262 was connected to the vented passage |65 in release position of the triple valve device and emergency valve device, the small reservoir 5| 'and the connected valve piston chamber |49 are at atmospheric pressure when an emergencyl application of the brakes is initiated in the manner above described. As a result, the inshot valve piston |45 is held in engagement with the seat rib |41 only by the force of spring |48. y

When the pressure of fluid being supplied to the brake cylinder 4 through passage |96 and acting on the seated area. of the inshot valve piston |45 within tle seat rib |41 .becomes sufficiently great to overcomethe resisting force of spring |48, said valve piston starts moving toward the left. Upon breakage of the seal with r the seat rib |41, the entire face of said valve piston is acted upon by the pressure of fluid being supplied to the brake cylinder, and said valve piston is thereby rapidly moved against the pressure of spring |48 into sealing engagement with a gasket 23|.

With the inshot valve piston seatedl on gaske 23|, the pressure of spring |44 moves the poppet valve 4| into engagement with seat rib |43, thereby closing the unrestricted connection between the supply passage |65 and the brake cylinder passage |96, as shown in Fig. 4 of the dra-wings. With the poppet valve |4| seated, fluid under pressure continues to flow from passage |65 to passage |96 and from thence to the brake cylinder 4 at a restricted rate governed by thel choke 232, by-passing the poppet valve |4|.

The pressure of fluid in passage |65 acts inside of the seat rib |64 on the timing valve diaphragm |51 and the area of said diaphragm outside of said seat rib is subject to the pressure of fluid in passage |96 Vthrough which fluid under pressure is being supplied to the brake cylinder and chamber |58 at the other side of said diaphragm is subject t0 the reducing quick action chamber pressure in the emergency valve chamber f|0|. When the increasing fluid pressures on the left hand side of said diaphragm plus the pressure of spring |61 become sufficient to overbalance the pressure in diaphragm chamber |58, said diaphragm is deflected away from the seat rib |64. The pressureacting withinsaid seat rib is greater than the pressure acting on the outside of the 4seat rib due to the restriction of choke 232, so

phragm and moves follower |60 into engagement with the lug |62, as shown in Fig. 5 of the drawings. This effects an unrestricted communication from passage |65 to passage |96, through which fluid under pressure is supplied from the emergency reservoir and auxiliary reservoir to the brake cylinder 4, and the brake cylinder pressure builds up to equalization with the pressure in said reservoirs.

Upon substantially complete venting of fiuid at quick action chamber pressure from the emergency valve chamber |0I, the pressure of spring ||1 in the emergency piston stem ||0 moves the piston 98 and auxiliary slide valve |04 relative to the main slide valve |03, but upon the force of said spring being expended, the movement of 'said piston and valve ceases. As a result, the main slide valve |03 remains in emergency position and maintains communication from the emergency reservoir 2 to the brake cylinder 4 through passage |86, cavity 230 and passage |65. Communication is also maintained between the auxiliary reservoir and brake cylinder 4 through the triple valve device in emergency, So that if there is leakage from the brake cylinder, the volume of pressure of fluid in cavities 230 and 233 by fluid at emergency reservoir pressure acting in chamber |2| on diaphragm |20, the pressure on said diaphragm being transmitted through the rocking pin ||8.

From the above description of effecting an emergency application of the brakes, it will be noted that, although the supply of fiuid under pressure to the brake cylinder is continuous from the start to equalization with the pressure of fluid in the auxiliary and emergency reservoirs, the build up is in three distinct stages. There is an initial quick inshot before the inshot poppet valve |4| seats, then there is a slow build up through choke 232 and finally a rapid build up past the unseated timing valve diaphragm |51. The initial inshot may be of any small degree, such as 15 pounds in the brake cylinder, which is not adapted to provide effective braking power, but its primary purpose is to set up a slight retardation for causing the slack in the train to gradually gather without causing severe shocks. The slow build up through choke 232 may increase the it is obvious that the three stages of brake' cylinder build up on, say the first and last cars -of the train would parallel each other and be spaced from each other by a degree of time equal to that required for transmitting quick serial venting of the brake pipe from the first car to thel last car. This operation is theoretical and would not be most desirable,'since it would be better to obtain a more nearly synchronous build up of brake cylinder pressure on the front and rear of the train in order to reduce to a minimum the undesirable and often disastrous running in of the cars at the rear of the train against those l at the front of the train, and according to the invention means are provided for attaining this result in the following manner.

It is well known that the brake pipe on a train of cars is subject to leakage and if the brake pipe leakage on a train of say 150 cars in length is for instance 15 pounds per minut-e, the brake pipe may be considered in good condition. Since fluid under pressure is normally supplied to the brake pipe at only one end, as at the locomotive, the brake pipe pressure at the front end of the train will be substantially equal to that supplied by the usual feed valve device. Due to leakage from the brake pipe through the train however, the brake pipe pressure will drop, and at the rear of the train theV brake pipe pressure will be lower than at the front of the train by a degree substantially equal to-the degree of brake pipe leakage. In other words, if the normal pressure supplied by the feed valve device is '70 pounds and there is 15 pounds per minute leakage from the brake pipe, the brake pipe pressure at the front end of the train will be 70 pounds but at the rear end of a train of say 150 cars length the brake pipe -pressure will be about pounds and this difference in brake pipe pressure throughout the y brake pipe on the train is commonly called'the brake pipe gradient.

If the brake pipe pressure at the rear of the train is built up to only 55 pounds, the brake equipments including the reservoirs and chambers will also build up to only 55 pounds and it is therefore obvious that the pressure in the timing valve diaphragm chamber |58 will also be substantially 55 pounds.

Ii now an emergency application of the brakes is effected, there will be the initial inshot of fluid under pressure to the brake cylinder by way of the open inshot poppet valve |4| in the same -manner as hereinbeiore described. This inshot will be substantially the same at both the front and rear of the train due to being governed by the pressure of spring |48 acting on the inshot valve piston |45, but the start of the inshot on the rear car in the train will be possibly 8 seconds after it is started on the first car, this 8 seconds being the time required to transmit the quick venting of brake pipe through the train of say cars length.

valve diaphragm |51 to deflect said diaphragmagainst the reducing quick action chamber pressure in chamber |58, after which the final rapid build up occurs as hereinbefore described. At the' front end of the train the quick action chamber pressure starts reducing, upon movement of the emergency valve device to emergency position, from 70 pounds, but at the rear of the train, the quick action chamber pressure starts reducing from say 55 pounds.` At the rear 0f the train the initial inshot and slow build up are at substantially the same rate as at the front end but occurs about 8 seconds later. Since the quick action chamber pressure is lower however, less brake cylinder pressure has to build up on the timing valve diaphragm |51 to shift it to its open position than is required at the front end, and this causes a shorter period of slow build up before the final rapid build up than is obtained. on the front end of the train', with the result that the final rapid build up, which produces the braking power for stopping the train, occurs at substantially the same time on the rear of the train as on the front of the train.

If the brake pipe leakage is greater than 15 pounds per minute, the time of the slow build up at the rear end of the vtrain is further-reduced, with the result that the final buildup 'application' is effected, the movement of the emergency slide valve |03 to emergency position laps passage 262 so that reservoir |5| and chamber |49 at the spring side of the valve piston |45 are at atmospheric pressure and said valve piston is moved from seat rib |41 when the brake cylinder pressure acting on the area of said valve piston within the seat rib |41 exceeds the pressure of spring |48, as hereinbefore described.

If an emergency application of the brakes is effected, however, on top of a service application of the brakes, the uid at brake cylinder pressure is trapped in reservoir |5| and chamber |49, when the emergency slide valve |03 moves to emergency position, so that the brake cylinder pressure 'acting on the valve piston |45 within the seat rib 41 must be built up to a correspondingly higher degree before the valve piston |45 will be shifted to permit closure of the valve |4|. A substantially uniform initial inshot of fluid under pressure to the brake cylinder is thus ef,-

fected in an emergency application of the brakes,

even though an emergency application is effected while the brakes are applied in service. This reservoir |5| .is merely provided for increasing the volume of the chamber |49 so that any leakage past the main emergency slide valve |03 or the valve piston |45 to chamber |49, can not seat. The by-pass passage 2,00 opening into `75 chamber |49 is provided to nsiire that the seated area of the valve piston |45 outside of the seat rib |41 is initially at atmospheric pressure, so as to prevent leakage from affecting the operation of the valve piston in controlling the initial inshot.

The purpose of the timing valve diaphragm follower |60 is to provide a largerbearing area for the diaphragm |51 so as to prevent damage to said diaphragm when it is deflected to its \right hand position.

To effect a release of the brakes after an emergency application, fluid under pressure is supplied to the brake pipe 31 and flows to the triple valve piston chamber 40 and to the emergency valve piston chamber 99. The triple valve piston 39 is subject in the valve chamber 42 to reduced auxiliary reservoir pressure, but the emergency valve chamber lill is at atmospheric pressure. Consequently, upon a slight increase in brake pipe pressure, sufficient differential is obtained on the emergency piston 98 to start moving said piston and theslide valves |93 and |94 toward the right hand. As hereinbefore described, thel choke |88 through the emergencyfY piston charnber wall is inadequate to offset the rapid rate at which the pressure in piston chamber 99 is increased at the head encl of the train, so that the piston 98 is moved upon a slight increase in brake pipe pressure, of for instance 7 pounds, to its extreme right hand or back dump position, in which said piston compresses the spring |08 and engages the stop lug 221.

In back dump position, passage |65, which is open to the brake cylinder through the open timing 'valve device |54, is connected through I cavity |99 in the emergency slide valve t0 a passage 234 leading tothe lower side of a ball check valve 235. Thus, fluid under pressure is permitted to flow from the brake cylinder 4 to the lower side of said check valve and unseat said valve against the pressure of spring 236 and then flow through/passage 240 to passage |34 leading to the brake pipe passage 38 in the pipe bracket portion' 6. Passage |65 is also supplied with fluid under pressure from the auxiliary reservoir through the triple valve device which is still in its service position. As a result, there ls a rapid iiow of fluid under pressure from the brake cylinder 4 and from the auxiliary reservoir to the brake pipe 31, which charges the brake pipe With fluid under pressure at a rapid rate. This action naturally occurs rst at the front end of the train where the increase in brake pipe pressure is rst effective, and the sudden increase in brake Apipe pressure caused by operation of the emergency valve device on the rst car causes the emergency valve device on the next car to operate in a similar manner and this operation is thus rapidly transmitted serially from car to car throughout the length of the train. This action effects several desirable results. It economizes in the use of fluid under pressure, it suddenly increases the break pipe pressure on the entire train from zero to about 40 pounds, thereby hastening the charging o f the train after an emergency application of the brakes, and finally, by reducing auxiliary reservoir pressure to a low degree and substantially to equalization with the brake pipe, it ensures movement of the triple valve device to effect a release of the brakes on the rear end of the train, as will now be described more in detail.

In effecting an emergency application of. the brakes, the pressure of fluid in the auxiliary and emergency reservoirs equalizes into the brake cylinder at approximately 60 pounds, assuming the brake pipe pressure to have normally been '70 pounds. In order to effect a release of brakes after an emergency application when the auxiliary reservoir pressure is not reduced as in the present case, the brake pipe pressure has to be increased above the 60 pounds in order to obtain a differential on the triple valve piston 39 for moving it and the slide valves 44 and 45 to release position. At the rear end of a train, the rate at which brake pipe pressure increases-from the supply through the usual brake valve device is ielatively slow and as it increases and approaches the pressure of the supply, the rate of increase reduces. It is thus obvious that the rate of increase at 60 pounds brake pipe pressure is slower' than it is at say 40 pounds brake pipe pressure and at 60 pounds it would be more difficult to obtain the releasing differential on the triple valve piston 39, particularly against possible leakage past said piston, than it is with the present valve device Where the auxiliary reservoir pressure in the triple valve chamber 42 is reduced to substantially 40 pounds.

After the brake pipe pressure is suddenly increased by the supply of fluid under pressure from the brake cylinder 4 and auxiliary reservoir 2, it continues to be charged in the usual manner. At the head end of the train, the supply of fluid under pressure to the brake pipe through the brake valve device in release position moves the triple valve piston 39 and slide valves 44 and 45 to retarded release position, in which the release of the remaining fluid under pressure from the brake cylinder is retarded by choke 2| l in the main slide valve 44, and fluid at the reduced pressure in the emergency reservoir 2 flows back and equalizes into the auxiliary reservoir, after which both reservoirs charge with uid under pressure supplied from the brake pipe past the triple valve piston 3.9 through feed groove 225. Upon moving the brake valve device to running position, the triple valve device moves from retarded release position to full release position, in which the final release of fluid under pressure from the brake cylinder and the charging of the reservo-irs and 2 occurs in the same manner as hereinbefore described in connection with releasing after a service application of the brakes. 'Ihe emergency valve device at the front end of the train is initially moved to its back dump position as hereinbefore described, but after the quick action chamber I3 and emergency slide valve chamber ||l| becomes charged with fluid under pressure supplied from the brake pipe through choke |88 to within possibly 3 pounds of the brake pipe pressure in piston chamber 9,9,- the spring |98 moves the emergency valve parts to their release position shown in Fig. 1, in which position the chambers I3 and |0| are charged up to brake pipe pressure through the choke |88. When the brake pipe pressure becomes increased above the brake cylinder and auxiliary reservoir pressures, it will be noted that the check valve 235 prevents back flow from the brake pipe to the emergency reservoir.

The release o f brakes and recharging of the auxiliary and emergency reservoirs at the rear end of the train after an emergency application of the brakes is the same as in releasing' after a service application, except that the emergency valve device is initially moved to the back dump positioned and then returns to release position, as hereinbefore described. The triple valve device is however not moved from the service position to release position by the sudden increase in brake pipe pressure effected through operation of the emergency valve device. As hereinbefore described, the brake pipe pressure is rapidly increased to possibly 40 pounds, but this pressure to release position. If said spring were not used and substantial equalization of pressures were allowed to occur in the brake pipe and auxiliary reservoir, then the pressure surges created in the brake pipe by the sudden back dump of fluid under pressure from. the auxiliary reservoir and brake cylinder into the brake pipe might cause the triple valve piston 39 to shift the slide valves 44 and 45 back and forth between service and release positions, causing alternately a partial release of the brakes and then a partial application of the brakes with a consequent drain and loss of fluid under pressure from the brake pipe, the auxiliary reservoir and emergency reservoir. Besides the loss of fluid under pressure through this action, the quick service action would be effective upon every movement from release to service position and in addition to this quick service action effecting an undesirable loss of fluid under pressure from the brake pipe, it would create additional surges in the brake pipe which would merely aggravate the unstable brake pipe condition. It has been found thatunder certain conditions of operation, the triple valve device is not unstable and does not operate as just described when the spring 236 is not em ployed, but realizing the proximity of this unstable condition, the spring 236 is employed to insure against such undesirable action and at the same time said spring does not reduce the degree of back dump to any appreciable extent.

After the triple valve device is moved to release position, the charging of the brake equipments and the venting of fluid under pressure from the brake cylinder to the atmosphere occurs in the same manner as after the tripple valve device moves to full release position at the front end of the train.

If due to breakage of spring |08 or for any reason said spring should not return the emergency valve piston 98 and slide valves |03 and |04 from the back dump position, shown in Fig. 2, to the release position, shown in Fig. 1, the emergency valve device will operate upon a service reduction in brake pipe pressure in the same manner as hereinbefore described, for the reason that the service vent port 222 through the emergency slide valve |03 opens into an enlarged portion at the slide valve seat which maintains communication with the atmospheric port 223 in back dump position, as well as in release position. If this were not so, and the pressure of.

fluid in the emergency valve chamber were not permitted to reduce upon a service reduction in 'brake pipe pressure, then the differential required on the emergency piston 98 to movesaid piston and the slide valves |03 and |04 from the back dump position might be such that their movement would not cease in service position, in which port 222 registers with the atmospheric lpassage 223, but the piston and slide valves would move to emergency position and cause an undesired emergency application ofthe brakes to be effected on` the train.

When a service application of the brakes is effected, the pressure of fluid supplied to the small reservoir and to the inshot valve piston chamber |49 for holding the inshot poppet valve |4| unseated, also acts thr ugh passage 262 on the seated area of the cut- )ut valve diaphragm |68 within the seat rib |13 but is insufficient in degree to move said diaphi agm from said seat and therefore has no effec 1. When an emergency application of the brakes is effected, fluid under pressure is supplied from the emergency reservoir passage |86 through passages |92 and 231, cavity 233 in the emergency slide valve and passage 238 to the seated area of the cut-out valve diaphragm outside of the seat rib |13, but as in effecting a service application of the brakes, this also has no effect upon the cut-out valve diaphragm in normal operation, as hereinbefore described, when the normal brake pipe pressure and consequently the pressure of fluid obtained in the emergency reservoir 2 is of a predetermined value such as 70 pounds.

In a short train the slack action is not so severe as in a long train and especially when short trains are used in high speed service the effect of slack is so reduced that it is substantially unnecessary to take the extremevprecautions as in braking a long train which may travel at a relatively slow speed. Accordingly, the cut-out valve device |55 isprovided for permitting a Arapid build up of brake cylinder pressure to occur on a short train upon an emergency application of the brakes. By thus rendering the inshot valve device |52 and timing valve device |54 ineffective to control the supply of iiuid under pressure to the brake cylinder 4 in effecting an emergency application of the brakes, a quicker application and quicker stop is obtained.

For controlling ashort, high speed train, it is usual to employ a higher brake pipe pressure than is employed in the ordinary long train serv`- ice hereinbefore described. As a result, the auxiliary reservoir and emergency reservoir 2 are charged to the higher brake pipe pressure, which may be for instance 90 pounds. When an emergency application of the brakes is effected with this pressure, the emergency valve device establishes communication from the emergency reservoir 2 tothe seated area of the cut-out valve diaphragm |68 outside of the seat rib |13, by way of pipe |81, passages |88, |92, 231, cavity 233 in the emergency slide valve |03 and passage 238. This high emergency reservoir pressure acting on the cut-out valve diaphragm is adapted to deflect said diaphragm away from the inshot valve chamber |49. 'I'he pressure of sure as when the brake pipe pressure is of the normal degree employed in long 'train service.

In controlling a train on a descending grade, it. is customary to cycle or in other Words to alternately effect an application of the brakes and then recharge the brake lequipmentsvvhile a 'partial release of the brakes is taking place through a retaining valve device. On a descending grade, the slack in a train is generally gathered against the locomotive at the front end oi the train, so as in short train service, it is proposed to employ a high brake pipe pressure, so that When an emergency application of the brakes is effected, the inshot valve device is rendered ineective to hold back the emergency build up of brake cylinder pressure. As a result, upon an emergency reduction in brake pipe pressure the brakes will be suddenly applied by a rapid increase in brake cylinder pressure effected in the same manner as in short train operation.

In cycling the brakes, the service application and releasing after a service application will however be slightly different from the normal operation hereinbefore described. ,The retaining valve device is turned to the usual cut-in position, so that in releasing afterthe initial application o-f the brakes, Which will be effected in the same manner as hereinbefore described, the retaining valve device 5 will close when the brake cylinder pressure is reduced to a predetermined degree, and thus bottle up a pressure in the brake cylinder 4 of for instance 20 pounds.

As described in connection with effecting a quick service reduction in brake/pipe pressure, the quick service modifying valve -diaphragm is deflected upwardly` against spring 12 by a predetermined low pressure, yof for instance 6 pounds, in the diaphragm chamber 62 and this permits the check valve 63'to seat, which prevents venting of uid under pressure from the 'quick service reservoir I4 until after the pressure has reduced in the diaphragm chamber 62 sufficiently below the 6 pound value of spring 'I2-to permit said spring to unseat the check valve 63.

'Ihe quick service modifying valve diaphragm chamber `62 is open in release position of the triple valve slide valve 44 to the retaining valve passage |98 through cavity 201, port 208, choke 299, port 2I0, choke 2II and cavity |91 and in retarded release position port 2I0 connects directly to the retaining valve passage |98. Thus, as fluid at brake cylinder pressure in passage |98 is permitted to reduce through the retaining valve device 5, the pressure of fluid in the modifying valve diaphragm chamber 62 and the connecting passage 206 reduces at the same rate and when the retaining valve device closes, fluid at brake cylinder pressure is bottled in said diaphragm chamber 62 and passage 206, and this bottled pressure is sufficiently in excess of the value of the diaphragm spring 'I2 that the check valve is retained seated by spring 66, so that no venting of iiuid under pressure is permitted to occur from the quick service reservoir I4.

While the brake cylinder pressure is thus being reduced down to the setting of the retaining valve device, the brake pipe, auxiliary reservoir I and emergency reservoir 2 are recharging in the same manner as in releasing after a service application. When the brake equipments are thus recharged to the desired degree, a reduction in brake pipe pressure may'be effected which causes the triple valve device to first move to quick service position, in which passage |00 from the brak-e pipe passage 38 is again connected to the quick service passage 206 through port 2I5 in valve diaphragm chamber 62.

the main slide valve 44, cavity 2| 4 in the auxiliary slide valve 45 and port 208. This permits a quick service venting of fluid under pressure from the brake pipe to passage 206 and quick service modifying valve diaphragm chamber 62, but not to the quick service reservoir I4 which at this time is charged with fluid under ypressure from the quick service action of the initial application of brakes.

The combined volume of passage 206 and diaphragm chamber 62 is such as to effect a sufficient but limited quick service reduction in rake pipe pressure to hasten the service action through a train, but the degree is less than upon the initial application when the quick service reservoir I4 is effective, for the reason that the additional quick service reduction which would be eected by said reservoir would cause too great an aditional application of the brakes and thus toa certain extent, take avvay from the engineer' the control of the degree of reapplication.

After the quick service reduction in brake pipe pressure is eiected, the triple valve moves to service position, in which the passage |00 is connected to passage 206 through port 2| 8, choke 2|'| and port 2I6 through which brake pipe pressure may gradually equalize from the brake pipe into the passage 206 and quick service modifying In service position uid under pressure is also supplied from the auxiliary reservoir I to the brake cylinder 4 and builds upon the retained pressure in the brake cylinder, thereby increasing the degree of brake cylinder pressure for slowing down the train. When desired, another partial release of the brakes and a recharge of the brake equipment may be eiected and then followed'by another application of the brakes. and this alternate operation may be continued as long as desired. after which a complete release of the brakes may be eiected by turning down the retaining valve device to cut-out position and a full recharge of the brake equipment may be obtained in the same manner as in releasing after a service application.

It is apparent that in order to vent uid under pressure from the quick service chamber I4, quick service modifying valve diaphragm chamber 62 and passage 206 when releasing the brakes, that the connection through port v208, choke 209 and port 2 I0 in the main slide valve 44 to the retaining valve passage |98 is provided in full release position of the triple valve device and in retarded release position of said triple valve device port 2 I0 is connected through the retarded release choke 2II to passage |98. As a result, the release of fluid from the quick service chamber is retarded either by choke 209 by itselfl or by chokes 209 and 2I| in series, but this slow venting has no operative effect, and in so far as such venting is concerned both chokes could be omitted, but these chokes are provided for other purposes. The object of the retarded release choke 2|I has been hereinbefore specified, but the purpose of choke 209 is to prevent any appreciable venting of fluid under pressure from the brake pipe to the retaining valve pipe |98 and from thence to the atmosphere when the triple Valve device moves to quick service position and supplies fluid at brake pipe pressure from passage |00 through cavity 2 I4 to the quick service port 206.

The choke |94 is provided to limit the rate at which fluid under pressure can'flovv to the emergency slide valve loading diaphragm chamber I2 I, so that if the diaphragm |20 should become ruptured and establish communication from the emergency reservoir 2 to the emergency slide valve chamber IDI, and a service application of the brakes is then effected, the service port 22| through the auxiliary slide valve |04 and port 222 in the main slide valve |83 will be able to reduce the pressure in said valve chamber at a rate suiiiciently fast to prevent obtaining a differential on the emergency piston 98 of a degree which would move it to emergency position and thus cause an'undesired emergency application of the brakes to be eiected.

At certain times it may be desired to vent fluid under pressure from the auxiliary reservoir and emergency reservoir 2 and for this purpose the reservoir release valve device 14, which is covered in my patents, Nos. 2,012,717 and 2,912,718, issued August 27, 1935 is provided. By moving the operating lever 91 of said :device in either direction, the sliding pin 88 is pushed downwardly against the pressure of spring 9| and carries with it the member 90 which first engages the auxiliary reservoir release valve stem 80, and upon further movement unseats said valve and engages the emergency reservoir release valve stem 81 so that still further movement will unseat the valve 83. If it is desired to vent iiuid under pressure only from the auxiliary reservoir I the member 88 is only moved suflciently to unseat the auxiliary reservoir release valve 15 which permits fluid under pressure to flow from the valve chamber 42 and connected auxiliary reservoir to chamber 8|, which is open to the atmosphere.

' If it is desired to vent iiuid under pressure from both of said reservoirs, the member is moved downwardly suiiicientlyto unseat the emergency reservoir release valve 83, as well as the auxiliary reservoir release valve 15, and this permits iiuid under pressure to owfrom the emergency reservoir 2 through pipe |81, passage |88 and past the release valve 83 to the atmosphere through chamber 8|, at the same time as fluid under pressure is released from the auxiliary reservoir through Certain features shown and described in this application are the invention of Clyde C. Farmer and are claimed in an application of Clyde C. Farmer, Serial No. 612,465, led May 20, 1932.

While one illustrative embodiment ofthe inven tion has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now Adescribed my invention, what I claim as new and desire to secure by Letters Patent, is:- Y

. 1.In a iiuid pressure brake, the combination with a brake cylinder and a normally open valve, of a triple valve device and an emergency valve device operated in effecting an emergency application of the brakes for supplying fluid under pressure to said brake cylinder past said open valve, movable means normally holding said valve open and operating upon an increase in brake cylinder pressure for permitting said valve to close and means for subjecting said movable means to brake cylinder pressure in a direction to oppose the movement of said movable means to permit said valve to close.

2. In a iiuid pressure brake, the combination with a brake cylinder, and a normally open valve, of a triple valve device operative in effecting a service application of the brakes to' supply iiuid under pressure past said open valve tosad brake the valve chamber 42 and past the release valve cylinder, an emergency valve device, said triple valve device and'said emergency valve device being both operative in effecting an emergency application of the brakes to supply fluid under pressure past said open valve to said brake cylinder, means operated upon an increase in brake cylinder pressure for permitting the closing of said valve in effecting an emergency application of the brakes, said emergency valve device establishing communication through which iiuid under pressure is supplied to said means, in effecting a service application of the brakes, to oppose the closing movement of said valve.

3. In a fluid pressure brake, the combination with a brake cylinder, and a normally open valve, of a triple valve device operative in effecting a service application of the brakes to supply fluid under pressure past said open valve to said brake cylinder, an emergency valve device, said triple valve device and said emergency valve device being both operative in eiecting an emergency application of the brakes to supply fluid under pressure past said open valve to said brake cylinder, means operated upon an increase in brake cylinder pressure for closing said valve in effecting an emergency application of the brakes, the closing movement of' said valve being opposed by brake cylinder pressure previously supplied to said brake cylinder in effecting a service application of the brakes.

4. In a fluid pressure brake, the combination with a brake cylinder, and a normally open valve, of valve means operated in effecting an emergency applicationo'f the brakes for supplying iiuid under pressure past said valve to said brake cylinder, movable means normally holding said valve open and operating upon an increase in brake cylinder pressure for permitting said valve to close, means for subjecting said movable means to brake cylinder pressure in a direction to oppo'se the movement of said movable means to permit said valve to close, and means for controlling the supplyof fluid under pressure from said valve means to said brake cylinder after said valve is closed.

5. In a iiuid pressure brake, the combination' on the closing of said valve, and means operated in accordance with the pressures in said reservoir in opposition to the pressure in the brake cylinder and to the pressure of fluid supplied by said valve means, for supplying iiuid under'pressure directly from said valve means to said brake cylinder independent of -said passage.

6. In a fluid pressure brake, the combination with a brake cylinder, a reservoir normally charged with fluid under pressure and a normally open valve, of valve means operated in effecting an emergency application f the brakes to sup-y ply fluid under pressure past said valve to said brake cylinder and to vent fluid under pressure from said reservoir, means operated upon an increase in brake cylinder pressure for closing said valve, a passage by-passing said valve for controlling the supply of fluid under pressure from 75 said valve means to said brake cylinder upon the closing of said valve, and means operated in accordance with the reduction in pressure in said reservoir for supplying fluid under pressure directly from said valve means to said brake cylinder independent of `said passage.

7. In a fluid pressure brake, the combination with a brake cylinder and a reservoir, of valve means operated in effecting an emergency application of the brakes for supplying fluid under pressure to said brake cylinder, means included in said valve means for restricting the rate of flow of fluid to the brake cylinder and for venting fluid under pressure from said reservoir, and a valve having one seated area normally subject to the pressure of fluid supplied by said valve means and another seated area normally subject to brake cylinder pressure, said valve being operative in accordance with the reduction in pressure in said reservoir to open direct communication from said valve means to said b'rake cylinder.

8. In a fluid pressure brake, the .combination With a brake cylinder, of valve means operated in effecting an emergency application of the brakes to supply fluid under pressure to said brake cylinder, valve mechanism for at one time controlling the supply cf fluid under pressure from said valve means to said brake cylinder and for varying the rate at which fluid under pressure is supplied from said valve means to said brake cylinder, and a valve device controlled by the pressure of fluid supplied by said valve means in effecting an application of the brakes and operated upon a predetermined increase in fluid pressure for rendering said valve mechanisrn ineffective to vary the rate at which fluid under pressure is supplied by said valve means to said brake cylinder.

9. In a fluid pressure brake, the combination With a brake cylinder and a reservoir normally charged with fluid under pressure, of valve means operative ineflecting an emergency application of the brakes to supply fluid under pressure from said reservoir to said brake cylinder, valve mechanism for varying the rate at which fluid under pressure is supplied by said valve means to said brake cylinder, and a valve device operative by fluid under pressure from said reservo-ir for rendering said valve mechanism ineffective to vary the rate of flow of fluid to the brake cylinder.

10. In a fluid pressure brake, the combination with a brake cylinder and a reservoir normally charged with fluid under pressure, of valve means Operative in effecting an emergency application of the brakes .to supply fluid under pressure from said reservoir to said brake cylinder, valve mechanism for varying the rate at which fluid under pressure is supplied by said valve means to said i brake cylinder, and a valve device operative by fluid under pressure from said reservoir for rendering said valve mechanism ineffective to vary the rate of flo-w of fluid to the brake cylinder, the supply of fluid under pressure from said reservoir to said valve device being controlled by said valve means.

11. In a fluid pressure brake, the combination with a brake cylinder and a reservoir normally charged with fluid under pressure, of valve means operative in effecting an emergency application of the brakes to supply fluid undei` pressure fro-rn said reservoir to said brake cylinder. valve mechanism for varying the rate at which fluid under pressure is supplied by said valve means to said brake cylinder, and a valve device for rendering said valve mechanism ineffective, said valve device comprising a spring, and an abutment movable against the opposing pressure of said spring by fluid under pressure supplied from said reservoir by said valve means, for establishing direct communication from said valve means to said brake cylinder.l

l2. In a fluid pressure brake, the combination with a brake pipe charged with fluid at a predetermined pressure, a brake cylinder and a reservoir normally charged with fluid at brake pipe pressure, of an emergency valve device operative upon a reduction in brake pipe pressure to establish a communication through which fluid under pressure is supplied from said reservoir to said brake cylinder, valve mechanism for varying the rate at which fluid flows from said communication to said brake cylinder, and a'valve device operative by fluid under pressure from said reservoir when said brake pipe and reservoir are charged to a pressure greater than said predetermined pressure for rendering said valve mechanism ineffective to vary the rato of flow of fluid under pressure to said brake cylinder.

13. In a fluid pressure brake, the ccanbinatien with a brake pipe, of a bracket to which said brake pipe is connected, and a triple valve device mounted on one side of said bracket and having a piston chamber adapted to be supplied with fluid under pressure from said brake pipe,

an emergency valve device mounted on anotherside of said bracket and having a piston chamber adapted to be supplied with fluid under pressure from said brake pipe, said bracket having a chamber, means for connecting said chamber to each of said piston chambers'a passage connecting said chamber to said brake pipe, and means disposed in said chamber for filtering fluid undei` pressure supplied from th'e brake pipe through said passage to said means.

14. In a fluid pressure' brake, the combination with a brake pipe, of a bracket to which said brake pipe is connected, and a triple valve device mounted on one side of said bracket and having a piston chamber adapted to be supplied with fluid under pressure from said brake pipe. an emergency valve device mounted on another side of said bracket and having a piston chamber adapted to be `supplied with fluid under pressure from said brake pipe, said bracket having a quck service reservor adapted to be supplied with fluid undr pressure from the brake pipe upon operation of said triple valve device, a quick action chamber adapted to be supplied with fluid under pressure from the emergency piston chamber, and a cavity connected to said brake pipe and to said piston chambers, and means disposed in said cavity for filtering fluid under pressure supplied from said brake pipe to said chambers and quick service reservoir.

15. In a fluid pressure brake, the combination with a brake cylinder and brake pipe, of a normally open valve, a triple valve device and an emergency valve device operated upon a sudden reduction in brake pipe pressure for supplyng fluid under pressure past said open valve tothebrake. cylinder, means operative upon va predetermined increase in brake cylinder pressure for closing said valve,l and valve means controlling a by-pass communicati n around -said valve, through which fluid un er pressure is supplied to the brake cylinder, the last mentioned valve means being subject to the pressure of a chamber adapted to be charged with fluid under pressure from the brake pipe.

16. In a fluid pressure brake, the combination with a brake cylinderand brake pipe, of a normally open valve, a triple valve device and an emergency valve device operated upon a sudden reduction in brake pipe pressure for supplying uid under pressure past said open valve to the brake cylinder, means operative upon a predetermined increase in brake cylinder pressure for closing said valve, and valve means controlling a by-pass communication around said valve, through which fluid under pressure is supplied to the brake cylinder, the last mentioned valve means being subject to lthe opposing pressures of the brake cylinder and a chamber adapted to be charged With fluid under pressure from the brake pipe.

17. In a fluid pressure brake, the combination With a brake cylinder and brake pipe, of a normaliy open valve, a triple valve device and an emergency valve device operated upon a sudden reduction in brake pipe pressure for supplying fluid under pressure past said open valve to the brake cylinder, means operative upon a predetermined increase in brake cylinder pressure for closing said valve, and valve means controlling a by-pass communication around said valve, through which fluid under pressure is supplied to the brake cylinder, the last mentioned valve means being subject to the opposing pressures of the brake cylinder and a chamber adapted to be charged with fluid under pressure from the brakel pipe, and means operating upona sudden reduction in brake pipe pressure for venting fluid from said chamber at a restricted rate.

18. In a fluid pressure brake, the combination with a brake pipe and a brake cylinder, of valve means operated upon a reduction in brake pipe pressure to supply fluid under pressure to said brake cylinder, valve mechanism for at one time varying the rate of said supply, and means operative independently of said valve mechanism accordingr to the pressure of said supply of fluid for rendering said valve mechanism either effective or ineffective to vary the rate of supply of fluid under pressure to said brake cylinder.

l9. In a fluid pressure brake, the combination with a brake pipe and a brake cylinder, of valve means operated upon a reduction inl brake pipe pressure to supply fluid u'nder pressure to said brake cylinder, valve mechanism for at one time varying the rate of said supply, and means conditioned, upon the operation of said valve means upon a reduction in brake pipe pressure, to render said valve mechanism effective when the normal pressure carried in'the brake pipe is of a certain degree and to render said valve mechanism ineffective when the normal pressure carred in said brake pipe is of a diiferent degree.

20. In a fluid pressure brake, the combination With a brake pipe and a brake cylinder, of valve` means having a release position and movable upon an emergency reduction in brake pipe pressure to an emergency position for supplying uid under pressure to said brake cylinder to effect an emergency application of the brakes, of valve mechanism normally conditioned to vary the rate at which fluid is supplied by said valve means.

formed by the bracket face, said piston chamber being adapted to be supplied with fluid under pressure from said brake pipe, said bracket having a chamber, means connecting the chamber in said bracket to said piston chambers, a passage connecting tlie chamber in said bracket to said brake pipe, and means disposed in the chamber in said bracket for filtering fluid under pressure supplied from the brake pipe through said passage to said means.

22. In a fluid pressure brake, the combination With a brake pipe and a brake cylinder, of a. brake controiiing valve mechanism operated upon a gradual reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder to effect a service application of the `brakes and operated upon a sudden reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder to effect an emergency application of the brakes, said brake con- -trolling valve mechanism comprising a triple valve device and an emergency valve device, an inshot valve device for controlling a communication through which fluid under pressure is supplied to the brake cylinder in eifecting both a service and an emergency application of the brakes, said inshot valve device being responsive to a predetermined brake cylinder pressure in effecting an emergency application for closing said communication and being unresponsive to brake cylinder pressure to close said communication in effecting a service application, and means included in said emergency valve device for conditioning said inshot valve device to be responsive or unresponsive to brake cylinder pressure to close said communication.

23. In a fluid pressure brake, the combination with a brake pipe and a brake cylinder, of a brake controlling valve mechanism operated upon a gradual reduction in brake pipe pressure for supplying fluid under pressure to the brakecylinder to effect a service application of the brakes and operated upon a sudden reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder to effect an emergency application of the brakes, said brake vcontrolling valve mechanism comprising a triple valve device Aand an emergency valve device, an inshot valve emergency application of the brakes, said inshot being unresponsive to brake cylinder pressure t0A Vclose said communication in effecting a service application, and means included in said emergency valve device for subjecting said inshot valve device to fluid pressure in effecting a service applicati'on of the brakes for rendering the inshot valve device unresponsive to brake cylinder pressure to close said communication.

24. In a fluid pressure brake,`the combination With a brake pipe and a brake cylinder, of a brake controlling valve mechanism operated upon a gradual reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder to effect a service application of the CII brakes and operated upon a sudden reduction in brake pipe pressure for supplying fluid under pressure to the brake cylinder to effect an emergency application of the brakes, said brake controlling valve mechanism comprising a triple valve device and an emergency valve device, an inshot valve device for controlling a communication through which fiuid under pressure is supplied to the brake cylinder in eecting both a service and an emergency application of the brakes, said inshot valve device being responsive to av predetermined brake cylinder pressure in effecting an emergency application for closing said communication and being unresponsive to brake cylinder pressure to close said communication in electing a service application, and means included in said emergency valve device for subjecting said inshot valve device to fluid at brake cylinder pressure in effecting a service application of the brakes for rendering the inshot valve device unresponsive to brake cylinder pressure t close said communication.

25. In a uid pressure brake, the combination with a brake pipe, of a valve device comprising a casing, a valve in said casing operable to vent fluid under pressure from the brake pipe, a cylinder formed in said casing, a piston in said cylinder for actuating said valve to vent fluid under pressure from the brake pipe, said piston having a normal position in which said valve is closed, said casing having a leakage groove formed therein and establishing communication from one side of said piston to the other when said piston is in Athe normal position, a gasket mounted on said casing, and means operated upon a sudden reduction in brake pipe pressure for supplying fluid under pressure to said cylinder to actuate said piston to close said leakage groove andvto open said valve and to then eng-age said gasket to prevent uid which may leak from said cylinder past the periphery of said piston from flowing to the atmosphere.

26. In a uid pressure brake, the combination with a brake pipe, of a vent valve device operable by uid under pressure to vent fluid under pressure from the brake pipe, said vent valve device comprising a casing, a valvein said casing operable to vent uid under pressure from the brake pipe, a piston mounted in said casing having a pressure side and a non-pressure side, a gasket mounted on said casing at the non-pressure side of said piston, said piston having a normal position in which saidv valve is closed and the pressure side of the pion is open to the non-pressure side through a leakage groove formed in the cas-- ing and operable by fluid under pressure supplied to the pressure side of the piston for closing said leakage groove and for actuating said valve to vent ui'd under pressure from the brake pipe and for seating against said gasket to prevent leakage of fluid from the pressure side of the piston, and means operable upon a sudden reduction in brake pipe pressure for supplying fluid under pressure to the pressure side of said piston.

27. In a fluid pressure brake, the combination with a brake pipe, an auxiliary reservoir and a brake cylinder, of a triple valve device comprising a main slide valve, a graduating valve and a piston for operating said valves, said triple valve device having an inner and an outer release position,` a communication through which fluid is supplied from the brake pipe to the auxiliary reservoir at a restricted rate in both release positions of the triple valve device, means for loading the main valve in the outer release position, and

means operative upon movement of the main valve to the inner release position for reducing the loading of the main valve.

28. In a uid pressure brake, the combination with a brakepipe, a brake cylinder, a chamber and means for charging said chamber with fiuid under pressure from the brake pipe, of means operated upon an emergency reduction in brake pipe pressure for venting fluid from said chamber at a restricted rate, and means constantly subject to the opposing pressures of said chamber and brake cylinder and operative upon a reduction in pressure in said chamber for opening a communication through which fluid under pressure is supplied to the brake cylinder.

29. In a fluid pressure brake, the combination with a brake pipe, a brake cylinder, a chamber and means rfor charging said chamber with fluid under pressure from the brake pipe, of means opl erated upon an emergency reduction in brake pipe pressure for venting fluid from said chamber at a restricted rate, and means constantly subject to the opposing pressures of the chamber and brake cylinder and responsive to a reduction in pressure in said chamber and an increase in brake cylinder pressure for opening a communication through which fluid under pressure is supplied to the brake cylinder.

30. In'a fluid pressure brake, the combination with a brake cylinder, a chamber, means for charging said chamber with uid under pressure from the brake pipe, and a normally open valve, of a valve mechanism operated upon an emergency reduction in brake pipe pressure for supplying fluid under pressure past said valve to the brake cylinder and for venting fluid under pressure from said chamber, means operated upon an increase in brake cylinder pressure for closing said valve, means for restricting the rate of flow of fluid to the brake cylinder when the valve is closed, and Valve means constantly subject to the opposing pressures of the chamber and brake cylinder and operative upon a reduction in the pressure in said chamber for opening a communication through which fluid under pressure is also supplied to the brake cylinder to increase the rate of flow of fluid to the brake cylinder.

3l. In a fluid pressure brake, the combination with a brake cylinder, a chamber, means for charging said chamber with fluid under pressure from the brake pipe, and a normally open valve, of a valve mechanism operated upon an emergency reduction in brake pipe pressure for supplying fluid under pressure past said valve to the brake cylinder and for venting fluid under pressure from said chamber, means operated upon an increase in brake cylinder pressure for closing said valve, means for restricting the rate of ilow of fluid to the brake cylinder when the valve is closed, and means constantly subject to the opposing pressures of the chamber and brake cylinder and responsive to a reduction in pressure in said chamber and an increase in brake cylinder pressure for opening a communication through which fluid under pressure is supplied to the brake cylinder to increase the rate of flow of fluid to the brake cylinder.

`32. In a fluid pressure brake, the combination with a brake pipe, of a triple valve device comprising a piston, and a main valve operated by said piston and having a normal release position and an application position, said valve having a cavity which is connected to the atmosphere in the normal release position and which is supplied with 

